1. Field of the Invention
The present invention relates to a perpendicular magnetic recording head which performs a recording action by applying a recording magnetic field perpendicularly to a recording medium plane.
2. Related Background Art
As is well-known, a perpendicular magnetic recording head includes a main magnetic pole layer and a return yoke layer which have front end faces exposed at a surface opposing a recording medium (medium-opposing surface) and are magnetically coupled to each other on the deeper side of the medium-opposing surface in the height direction, a magnetic gap layer interposed between the main magnetic pole layer and return yoke layer on the medium-opposing surface, and a coil layer inducing a recording magnetic field between the main magnetic pole layer and return yoke layer upon energization. The recording magnetic field induced between the main magnetic pole layer and return yoke layer perpendicularly enters a hard film of the recording medium from the front end face of the main magnetic pole layer and returns to the front end face of the return yoke layer through a soft film of the recording medium. This performs magnetic recording at a part opposing the front end face of the main magnetic pole layer. The size in the track width direction of the front end face of the main magnetic pole layer, i.e., recording track width size, has been becoming narrower as hard disk drives have been attaining higher recording densities.
In a perpendicular magnetic recording head having a narrowed track, how to suppress side fringing at the time of skewing where the head is driven in a state tilted with respect to a recording medium has become a problem. As a method of suppressing side fringing at the time of skewing, it has been known to provide a magnetic shield layer for absorbing magnetic fluxes leaking from sides of the main magnetic pole layer in the vicinity of the main magnetic pole layer so as to enhance the recording magnetic field gradient. Examples of such a magnetic shield layer are described in Japanese Patent Application Laid-Open No. 2005-92929, Japanese Patent Application Laid-Open No. 2005-310363, Japanese Patent Application Laid-Open No. 2005-182987, Japanese Patent Application Laid-Open No. 2004-127480 and Japanese Patent Application Laid-Open No. 2006-134540.